In recent years various types of minute catheters have been developed for introduction into small body cavities and small vessels such as blood vessels in humans and animals. Often those minute catheters are very flexible and virtually lacking in rigidity. Furthermore, in many uses, the catheters are of great length and are extended along rather tortuous and extended paths within the body to reach desired locations.
One type of catheter which falls within this general category and criteria, is the small minature balloon catheter which has been recently developed for brain use. The catheter is threaded through tiny blood vessels in the brain into very remote locations for diagnostic and therapeutic purposes. When the catheter has reacted the desired location, it is subjected to various uses for treatment purposes including the introduction of fluids to the various sites or for expanding the minature balloons to lock the catheter at a particular location and often to occlude the minute vessel for further diagnostic and therapeutic purposes.
Naturally in order to limit the chances of injury to the patient and to allow it to be directed long distances by natural blood flow, it is desirable to have the most flexible and least rigid structure as possible for the member or catheter being introduced. This naturally presents various problems. For example once the rigidity is removed from the member, it is extremely difficult to advance the member into the vessel properly. For larger catheters, various guide wires and similar members have been utilized in the past for this purpose.
More recently, attempts have been made to replace the guide wires which can only be used on the larger catheter, due to the size required for proper functioning, with a suitable method for the minute catheters. As a replacement, various fluid delivery systems have been developed as exemplified by U.S. Pat. Nos. 3,703,174; 3,826,256; 3,911,927; and 3,982,544.
It is clear that the field of minature catheterization, particularly dealing with minute vessels in the brain is a new and fast developing medical art. Accordingly, advancement in the manner in which these catheters are handled and placed which protect the patient from trauma and possible harm are greatly desirable and needed as the techniques of the field develop.